# str1 = '@扎克伯格@俞敏洪@马云@马化腾' #好友列表
# print ('字符串“',str1,'中包括',str1.count('@'),'个@符号')


# str1='@扎克伯格@俞敏洪@马云@马化腾'
# print('字符串“',str1,'中@符号首次出现的位置为:'str1.index('*'))

# list_friend = ['扎克逼格','俞敏洪','马云','马化腾',]
# str_friend = ' @'.join(list_friend)
# at = '@'+str_friend
# print('您要@好友:',at)

# verse = ["春眠不觉晓","处处闻啼鸟","夜来风雨声","花落知多少"]
# print(verse[2])
# print(verse[-1])

nba = ["乔丹","拉塞尔","贾巴尔","邓肯","张伯伦","詹姆斯","哈登","伯德","奥尼尔","姚明","科比布莱恩特"]
print(nba[1:5])
print(nba[0:5:2])